Abstract

A new optical probe technique using a laser-trapped erbium oxide nanoparticle (~150 nm) can measure absolute temperature with a spatial resolution on the size of the nanoparticle. This technique (scanning optical probe thermometry) is used to collect the thermal image of an optically excited gold nanostructures. The thermal profile has a Gaussian line shape that is a convolution of the point spread function of the scanning optical probe thermometer and the true thermal profile. A convolution analysis reveals that the point spread function of our measurement is a Gaussian with a FWHM of 165 nm. We attribute the width of this function to clustering of Er2O3 nanoparticles in solution. Also, the scanning optical probe thermometer is used to measure the temperature where vapor nucleation occurs. Subsequently, the temperature inside the vapor bubble rises to the melting point of the gold nanostructure (~1300) where a temperature plateau is observed. The rise in temperature is attributed to inhibition of thermal transfer to the surrounding liquid by the thermal insulating vapor cocoon. This chapter is reprinted (adapted) with permission from Applied Physics A. (2016) 122: 340. Copyright 2016 Springer.